Ceramic matrix composites (CMCs) have a higher temperature capability than metallic alloys, making them potentially very valuable for implementation into gas turbines, which can run at temperatures well in excess of metal capabilities. Metal is stronger and more ductile, making it better for supporting hardware, such as vane carriers, casings, bolting, etc. To combine the advantages of these two materials, at some point they must attach to one another. However, attaching low alpha (low thermal growth) CMCs to higher alpha metals is not a simple procedure. In dynamic environments, the CMC and metal need to be rigidly attached to prevent vibration, which may lead to wear and/or fatigue issues. But, if high temperatures are also present, the metal and CMC will grow at different rates. If they are rigidly attached, the metal, being stiffer and stronger, will take the CMC with it. CMC is by nature more brittle and less strain-tolerant than metal. Such movement could damage, or even destroy, the CMC. The trick is to design an attachment that satisfies both these concerns—vibration and thermal growth.
In addition, in curved structures, any thermal gradient will cause the metal and CMC to not just linearly grow, but also curl or uncurl, depending on the thermal gradient characteristics. The attachment must therefore allow for such curling, and even take advantage of it.
There are also cases where the CMC structure is large enough, or carries enough load, that it requires multiple attachment regions but is still one structure. A second attachment region must allow for thermal growth of a CMC part away from a first attachment region, in addition to the metal it is attached to. This invention is a solution to these design considerations.